feat: add codegraph tool for querying pre-computed codebase dependency graph

- Implemented `tools-codegraph.ts` to provide various queries on the codebase dependency graph, including impact analysis, dead code detection, module boundaries, and more.
- Created a schema for validating query inputs using Zod.
- Developed helper functions for resolving file paths, formatting output, and handling different query types.
- Added tests for the codegraph queries in `codegraph-queries.test.ts` to ensure functionality and correctness.
- Introduced tests for the codegraph scanning and loading functionalities in `codegraph.test.ts`, verifying the detection of source files, imports, exports, circular dependencies, and entry points.

.gitignore

@@ -1,6 +1,6 @@
 # dependencies (bun install)
 node_modules
-
+.shiro/
 # build output
 out
 dist